Shadow Recruiter
by waterbaby134
Summary: The team attempts to talk Bruce into joining them on the battlefield more regularly. Each one fails, until Natasha steps up to the plate with a different approach, that complicates things for both of them. A Bruce/Nat story, guest-starring the rest of the crew, but no smut.
1. Chapter 1

**I've never written for this fandom before, but I really like the idea of this pairing (Bruce/Natasha) and wanted to try something new. Obviously, Bruce and Natasha will be the main characters but Cap, Iron Man, Thor, and Hawkeye are all mentioned.**

 **So this is set post-Avengers, pre-Ultron. For the purposes of this story, all Avengers except Thor, are living in the Tower.**

 **I have not read the comic books, and I apologize for any technical mistakes that may come of this.**

 **I own nothing recognisable.**

 **I hope you will give this a try and enjoy it.**

* * *

It's Steve who first raises the idea. He and the other Avengers (with the exception of Thor, who's in Asgard, and Bruce, who point blank refuses) have been kept busy responding to various calls for help around the globe. Nothing quite to the dramatic scale that was the Battle of New York, mind you, but there are more than enough terrorists and traffickers and dangerous people with more money and power than sense to keep the quinjet in the air fairly regularly.

Steve knows that the team of himself, Stark, Romanoff and Barton is enough to tackle most Earth-bound emergencies. He knows that if necessary, or if the problem becomes otherworldly, Thor will usually be willing to descend from on high and help out (he's fond of Earth, after all, and it gives him an excuse to see Jane Foster.) But even with all this, he knows that without Bruce Banner (or more specifically, the Hulk) the team is not as strong as it could be.

He can understand Banner's distaste for fighting, and he can't even begin to understand what it must be like to carry the kind of burden that he does. An entire other identity that is rage and raw power and thirsts for battle, with no sense of his own self to temper it. But the Hulk is the Avengers' trump card, their edge, the one that strikes fear into their enemies more than any other. The mere sight of the menacing green figure is enough to send the weaker-willed souls screaming in the opposite direction, and the rest follow quickly once they've experienced what he can do.

As a human being, Steve Rogers will always sympathize with Banner's plight. But as Captain America, a soldier and a strategist, Steve is also unable to ignore the simple truth; the Hulk is an asset in battle. He wants him to fight. And unfortunately, there's no way of having the big guy involved without Banner in tow. They're a package deal.

Banner unsurprisingly doesn't like to talk much about this subject, but from the rare occasions that he does, Steve has deduced that it's the lack of control, and fear of harming the innocent that most distresses Banner about his _other_ side. What they need is a way to rein the Hulk in when the job's done and get Banner back into control over his own mind before the Hulk does the kind of damage that can't be repaired. Since he woke up, Steve has seen more things in the world that he thought were impossible than he's had hot dinners. Very little seems impossible to him anymore. There has to be a way.

He presents his theory to the team over dinner one Tuesday, and the reactions he receives are mixed, to say the least. Banner is horrified, Stark thinks it's a brilliant idea, Barton looks apprehensive, and Romanoff makes no outward reaction whatsoever, but he can practically hear the gears turning in her mind. He'd be prepared to bet a twenty that she's already thinking about how they could do it.

He catches her eye and they exchange a glance. Natasha Romanoff has spent her whole life fighting. She's been trained for it since childhood and she's been fighting ever since. If anyone knows how valuable an advantage like the Hulk is in battle, it's her. If he had to guess, he'd say that she agrees with him on this, but he never really can tell with Natasha. With the occasional exception of Barton, nobody sees anything she doesn't want them to see. It can be unnerving sometimes, but that's a small trade-off for what she brings to the team, which is a lot more than just a deadly aim and a lethal roundhouse kick.

So Stark's in, and Romanoff seems to be too. That's half the team on board; a good start. But Banner is the one this most concerns, so he's the one they need to convince.

Banner takes off his glasses, polishes them on the hem of his shirt and then replaces them, clearly playing for time. "Steve, are you out of your mind?" he asks, once he's recovered enough from the surprise to speak. "I thought we'd agreed on this. New York was a one-time only situation."

"Oh come on, Bruce!" Stark jumps into the conversation before Steve can even open his mouth. "You always want to hear the gory details of the missions when we get back, I know a part of you still wants to be out there with us, kickin' ass."

Banner aims an irritated look at his self-proclaimed 'science bro.' The two of them tend to spend most of their time together when there's no mission, shut up in one of the tower's state-of-the-art labs from whenever Stark deigns to stumble out of bed, till late into the night. Steve has no idea what they're doing in there; when they discuss their work in the earshot of the others, they tend to speak in fast-paced technical jargon he doesn't understand. His theory is that they're both so pleased to have found a friend as intelligent as themselves, the fact that other people don't speak 'science genius' slips their minds.

"It's not that simple Tony. You of all people should know that. Otherwise why have we spent the last two months designing Veronica?" By the hard look he gives Stark, clearly this is supposed to have some kind of significance.

Whatever reaction Banner was intending to evoke, apparently fails. Stark looks neither cowed nor apologetic. "Veronica's a last resort," he replies, typically unruffled. "And she's nearly ready. Even more reason that you shouldn't worry."

The rest of the team exchange glances, and then Barton sighs. "OK, I'll bite. Who's Veronica?" he asks.

"A friend of the big green rage monster," says Stark smoothly, and when pressed, uncharacteristically declines to say any more on the subject. Usually, anyone foolish enough to show even the slightest interest in whatever they're doing in that lab is treated to a full breakdown of every detail, from conception, to planning, to setbacks faced. Steve makes a mental note to investigate this further at a later date. Banner and Stark are clearly up to something, and that thought unsettles him. Secrets aren't good for a team, especially one that flies into mortal danger every other week.

The discussion goes on for a long time. As expected Banner is highly reticent to do any more experimenting that concerns his other self.

"This isn't a simple trial-and-error situation that we can just keep repeating till we get it right," he points out. "What happens if something goes wrong? I won't be able to stop the Other Guy from going on the rampage, and any one of you could get caught in the crossfire." Bruce throws a guilty look at Natasha as he says these words. It's been months, and he's still torn up about the incident on the SHIELD helicarrier. She could have easily been killed, and he credits the fact that she's still breathing more to luck than good management on his part.

The thought of any of his friends falling victim to the Other Guy's rage is more than he can bear, but for some reason, picturing _her_ mangled body inspires an extra layer of dread. He's not entirely sure why. He's lot closer to Tony than Natasha, and it's no secret that the position of her greatest ally and confidante is occupied by Clint. Maybe it's some residual, psychological thing because she's a woman. He has to force himself not to cringe at the thought, and makes a vow to never _ever_ speak aloud any thought of the kind. She wouldn't appreciate it. She's far more capable than any military man he's met (excepting Steve, of course) and she holds her own in their ragtag team of crime fighters without any superpowers or chemical enhancements or shiny metal suits.

Put simply, she is exceptional. But all the assassin training and hand-to-hand combat prowess in the world won't save her from the Other Guy. It was a close call last time. Too close. It's his responsibility to ensure that it doesn't happen again. Not to her, or any of the rest of the team.

Bruce can see Steve gearing up to come at it from another angle, and he is rapidly losing patience with this conversation.

"Look guys, I understand where you're coming from," he says, mostly addressing Steve, but making sure to glance around the table to include them all. "But this is not what I signed up for when I moved in here. I'm happy to help Tony come up with new tech, and to continue my work in the labs, but I'm not going to fight."

He never once raises his voice, but the team knows him well enough to realize that for now at least, the discussion is over. He stands and leaves the table, ignoring Tony and Steve's disappointed looks, and Clint's relieved one. He can feel Natasha's gaze on him as he retreats for the safety of the lab, but avoids her eye too. She probably thinks he's a coward now, and she'd have every reason to. But he'll take cowardice over killing machine any day of the week.

As the door slams shut behind Bruce, Steve sighs.

"Well, that was a waste of time," he says, irritably. He's used to being undermined by Stark and his trademark sarcasm, and Romanoff's dry wit, but defiance from Banner is unusual. Ironically, Bruce Banner, their resident green rage monster is probably the most even-tempered of the team and more often than not, is the peacemaker in situations like this.

"Did you really expect anything else?" asks Clint, leaning back in his chair as the tension that was filling the room begins to dissipate. "Banner's always been pretty clear about where he stands on this."

"But if he would just look at it differently," Steve persists, "he'd understand why."

"You're a soldier, Cap," Stark casually interjects. "Banner's not. You volunteered for the superpower upgrade. He didn't. You embraced your hero life, and all he wants is to make it stop. Hate to break it to you, but I don't think he's going to see this your way."

"Jeez Stark, when did you start getting so in touch with Banner's mental health?" asks Clint, with a hint of a smirk. "If you don't watch out people are going to think you've actually got _feelings_."

He and Natasha both snort with laughter, as Stark tries, and fails, to look offended.

"Nobody's perfect," he shrugs. "But I'm pretty much as good as it gets."

"Keep dreaming," says Clint, as Steve and Natasha roll their eyes.

As usual, criticism rolls off Tony Stark like water off a duck's back and he rises from his chair. This meeting, apparently, is now over. He claps a hand on Steve's shoulder as he passes him, heading for the kitchen.

"As much as I hate to agree with you, I'm with you on this one, Capsicle," he says. "Give Bruce some time, he'll come around."

* * *

Bruce escapes to his lab, to examine the results of a test he's been running, and to fume in peace. He asks JARVIS not to let anyone in, not even Tony, though he knows that if it comes down to it, Tony will simply override his AI and come in anyway. He'd like to think that his friend would appreciate that he wants to be alone right now, but subtlety and tact have never been Tony Stark's strong points.

He'd always thought Steve would get it, would understand why he doesn't want to do this, but he realizes now that the soldier instinct of Steve Rogers never truly switches off. He's probably been gearing up to this conversation for weeks. And Bruce can see where he's coming from. Hell, if he were in Steve's position, he'd probably want the same thing.

But he's not in Steve's position. Steve Rogers gets to be Captain America, paragon of righteousness, all-American hero, while Bruce Banner has to be a rage-fuelled creature, with almost unlimited strength, and no way to control it. A ticking time bomb. He can't agree to this plan.

He won't.

It's been a month since Steve first dropped the Hulk bombshell, and, true to his word, Bruce has not given in. Steve, Tony and even Thor one day when he'd dropped in for a visit, have each tried to convince him to reconsider, in their own distinct ways.

Steve appeals to his sense of duty to the team, to the country, to the world.

Tony promises upgrades to Veronica, upgrades to the jet, and every kind of complicated technological gadget he can dream up to help control the Other Guy, a safety net for if things go sideways.

Thor, who has always been a demigod of few words, keeps it relatively simple. "You have the power of a great warrior, Dr Banner. Do not fear it."

Irritated as he is that they won't let this go, he is polite to them when they bring it up. Polite but firm. Each receives a flat-out no.

Barton hasn't been keen on the idea from the start, and they don't have much to do with each other anyway, as a general rule. He's not one for science stuff, and Bruce tends not to frequent the gym a few floors down where Barton and Romanoff often spar.

That only leaves one person to take a shot at convincing him, and he'd be lying if he said he wasn't a little wary of her. Any intelligent person would be and he likes to think, without too much ego, that he is more intelligent than most.

She finds him one day when he's in the kitchen, eating a bowl of cereal and reading over last night's results. He and Tony have run into a problem with the latest project they're working on, and ran some tests late last night to try and figure out where they're going wrong. Most of Tony's fanciful gadgets aren't really in his ballpark, but he appreciates that a second set of eyes on a problem is always useful. It also has the added bonus of keeping Tony busy enough to not pester him anymore about the Other Guy.

He glances up, and starts a little when he sees her, standing at the kitchen island, holding an apple. Of course, he didn't hear her come in; he gets pretty focused on his work, and she can move around with complete stealth when she wants to. She's not wearing her slinky black catsuit today, so it's probably not a mission day. He's not sure what she does on days when she's not working; she tends to keep to herself most of the time. Occupational hazard of being a spy, he supposes.

"Morning, Doc," she greets him, with that tiny little smile that either means she's pleased to see him, or laughing at him, he's never been able to tell which. "What'cha got there?"

The question surprises him. Rarely does she ever initiate conversation, and when she does, she's never shown the slightest interest in his work. This has to be about the Hulk plan.

"Numbers, figures, equations. Nothing that would interest you, I assure you." He regrets the words as soon as they're out of his mouth. One sentence into this conversation and he's already managed to insult her. Great work Banner.

She crooks an eyebrow. "You calling me stupid, Doc?"

"Of course not, Miss Romanoff, I just…uh…"

See, this is why he embraced science and math in his youth, because he's hopeless at talking to women and always has been. Betty was a notable exception, but even she would never accuse him of being smooth when it came to the fairer sex.

Back comes that little grin, but this time he doesn't doubt that she's laughing at him, and well she might. He's a worldwide authority on gamma radiation, published in countless scientific journals, but right now he can't even seem to string a sentence together.

"Relax," she says, with a hint of humour in her voice. "You were right, I've never been much for the technical jargon if I can avoid it. And I'm not much for the formalities either, at least not among friends, so you can drop the 'Miss Romanoff' too."

"Friends?" he echoes, stupidly. Tony is his friend, sure, and Steve, and Pepper, and maybe Thor, at a stretch, but he never considered the relationship between himself and her as friendship. They have a healthy respect for each other's abilities, and a friendly acquaintance at best, but not friendship. He always figured that ship sailed when the Other Guy tried to crush her into a pulp.

But apparently, once again, he has misread her, as she shrugs. "Sure," she says. "We're teammates aren't we? Live in the same building, like the same kind of movies? No deeply repressed, burning hatred for each other? Well, at least not on my end, how about you?"

"Of course not," he manages to answer, remembering just in time not to tack the 'Miss Romanoff' on the end. Of all the ways he expected this morning to pan out, this odd conversation with the Black Widow is not one of them.

"That settles it, then," she says, seeming satisfied. "See you around, friend." She takes a bite of her apple, and departs.

It's only about an hour later, when he's watching Tony frantically press buttons on his holographic screen and bark orders to JARVIS to run the new algorithm he's just come up with, that he realises that she didn't mention the Other Guy at all.

* * *

He doesn't see her for a few days after that; she and Clint have a mission and he and Tony have managed to come up with a solution to their problem, so they're basically in the lab from daybreak until well into the night, until the night Pepper marches in and demands they take a break. Tony attempts to argue with her, but she puts her foot down, and within ten minutes he meekly puts down his tablet and follows her out of the lab. Bruce follows suit; this project is Tony's brainchild and design, there's just no point continuing on without him.

Pepper bullies Tony into a semi-respectable outfit, and off they go for a quiet dinner somewhere nearby. Of course, Tony and 'quiet' rarely can be used in the same sentence, but there's apparently a little place round the corner they often frequent that doesn't feel the need to trumpet the fact that Iron Man likes to eat there.

Pepper, polite as always, invites him to join them, but he declines. He's not about to play third wheel. He contents himself with waving them off from the doorway, and then decides to occupy himself with the newest issue of a scientific journal he subscribes to. Before he can retrieve it, however, JARVIS announces that 'Agent Romanoff has arrived.'

She looks a little worse for wear, not quite as put together as usual. He surmises that the mission probably didn't go as smoothly as Fury had initially hoped. Story of their lives.

"Where's Stark?" she demands, by way of greeting.

"He and Pepper went out for a date night."

She rolls her eyes. "Great. Stark's out getting laid, while I'm in life or death situations with malfunctioning equipment." She brandishes one of Tony's 'new and improved' Widow's Bites at him, which isn't glowing like it should be. "Damn thing short-circuited or something, nearly zapped _me_ instead of the bad guy."

"Are you all right?" he enquires. She doesn't look injured from what he can see, just pissed off, but she's the type to conceal an injury in order not to seem weak. It's a particularly dangerous habit of hers, he's noticed. Several times he's overheard Barton scolding her for it. No doubt he is the only one she'll allow to do so; if anyone else tried it, she'd flatten them, and that includes Steve, super soldier or not.

Predictably, she shoots him that usual coy smile and assures him that she's just fine. He's still not buying it, but it's not his place to pry. As she's amply proved many times over, she can take care of herself.

"Don't often see you outside of the lab at this time, Doc," she says instead. "Shouldn't you still be bent over a microscope or something?"

"Tony and I are banned from the lab for the next twelve hours," he answers. "Pepper's orders."

"And Stark agreed to that?"

"She didn't really give us a choice in the matter. I believe her exact words were 'either you two take a break or I'm telling JARVIS to lock you both out of all the labs and putting an end to your little science club.' She knows how to override every system. Tony taught her how in case there was an emergency."

"Bet he's regretting that now." She sinks into an armchair, and he notices that her movements are laboured, and she's favouring her left arm. She doesn't wince, or give any indication that she's in pain, but he knows the signs of an injury when he sees them. He can't ignore this any longer.

"You're hurt. Let me see," he requests.

"I'm fine."

"Come on…"

"I'm _fine_. I've had worse knocks than this from being jostled on the sidewalk," she jokes, but he is distinctly unamused.

"Let me see," he repeats, and inside, his frustration stirs the Other Guy. Banner pictures him sitting up and sniffing the air, awaiting his cue. But it won't be happening today.

She eyes him coolly from her armchair for a few moments and he's sure she's about to either punch him, or leave the room. He'd deserve either one, for prying into her business like this, and he can't quite believe he's doing it. This is so unlike him, he has enough grievances without taking on other people's too. But this feels different somehow.

She regards him for another few seconds and he's not sure which of them is the more surprised when she holds out her arm. Gently, he pushes up her sleeve to reveal a long, deep gash. Not life-threatening of course, but definitely in need of stitching, and sooner rather than later. Medical doctoring isn't really his forte, but this he can do.

Her skin is smooth. He's not sure why that's relevant, but apparently it is, because now he's noticed it, he can't seem to _stop_ noticing it.

"I can stitch it up for you," he offers. "Save you a trip to SHIELD medical."

She tugs her arm back again, and shrugs carelessly. "I can take care of it."

"I know you can, and probably better than I can, but I thought you said we were supposed to be friends. And you don't have to be the Black Widow all the time. Let someone help _you_ , for a change."

She says nothing in response to this uncharacteristically impassioned speech of his, but simply smiles and holds out her arm once more.

It takes him thirty minutes, to stitch, clean, and dress the wound, and neither of them speaks the whole time. He is too intent on his task, and she is watching him equally intently, no doubt noting the many mistakes he's making that she could have done better.

"What do you think?" he asks, as she inspects his handiwork. His professional pride is on the line here, after all.

"Not bad, Doc. Not good as me, of course-"

'Of course."

"But not bad at all."

That's high praise from Natasha Romanoff, and he takes it as such, pleased he was able to do her this small assistance and make up in even the tiniest way for the helicarrier.

"You know, we could use a medic on missions sometimes," she says, slyly, and he eyes her suspiciously.

"What?"

She shoots him an innocent smile that he doesn't believe for one second. "Just saying."

He waits for her to launch into the same "Hulk Could Be An Avenger Too' sales pitch the other three did, but, as he might have expected, she's more subtle than that, and lets the subject lie. At least for now.

"You could try being more careful," he suggests, probably pointlessly.

That gets a laugh out of her, albeit a hollow one. "No way, Doc," she says. "Where's the fun in that? Anyway, It's been a long day," she says, abruptly, getting to her feet. "I'm going to go sleep for the next three days. I'll leave the door open, so you can check my stitches during the night if you want."

He recognises the last comment as an attempt to throw him off his stride, and stop him lecturing her. Of course, she could simply tell him to mind his own business, but that doesn't seem to be her style. She's not the Black Widow for nothing; most men are playthings to her. But unlike the others, he _knows_ that she's just screwing with him.

"I think I'll leave that in your more than capable hands" he replies. "Goodnight, Miss Romanoff."

"What have I told you about that?" she chides him gently, and there's a playfulness about her that he hasn't seen before. "It's Natasha, not Miss Romanoff. If I have to correct you again, I'll beat it into you instead."

He'd like to see her try. But as she rises to leave, there's a certain unsettlement about him. He's only felt something like it once before, long ago, with a different woman, and when he was another man.

It's a complication he doesn't need, and that she certainly wouldn't want. But it only gets worse when she throws that damned half-smile over her shoulder at him as the elevator arrives.

She's a beautiful woman. Of course, he knew that already, but he doesn't think he's ever really appreciated it properly until this moment. And he can't believe it took him so long.

"Night, Bruce," she calls out softly to him as the doors close. Unhelpfully, his mind pipes up that she rarely uses his given name, and that he quite likes the way she says it.

Great. The Other Guy is more than a test for his emotional stability, and he knows he's not even slightly equipped to deal with something like _this_. Give him an equation or some complicated theorem any day.

He leans well back in the chair, removes his glasses, and rubs a hand over his eyes. Get a grip, Banner. He's not a geeky high schooler with a crush on the cute girl from homeroom; he's a grown man with responsibilities, chief of which is keeping the Other Guy in check. It's dangerous, the way he reacts to her pushing his buttons because he's not completely in control of it, and that terrifies him.

Bruce Banner doesn't get to have a normal life, he learned that long ago, but he can still try to keep the Other Guy's impact on it as minimal as possible.

And that means, avoiding anything that gets his heart racing, no matter what, or _who_ it might be.

* * *

 **I hope you found something about this to enjoy. I enjoyed writing it. These two are challenging characters, and I am hoping to explore their growing bond in a way that feels true to them, perhaps in another chapter, if people like this one.**

 **Thanks for reading!**


	2. Chapter 2

**Welcome to Chapter 2 of Shadow Recruiter. Thanks for your positive responses to Chapter 1. They inspired me to continue on.**

 **In this chapter you'll find heavy involvement from the entire Avengers team, plus the promised Bruce/Nat woven throughout. I envision this story to go to three or four chapters, and it will end pretty much where Age of Ultron begins.**

 **Trigger warning for a mention of suicide.**

 **Hope you enjoy!**

* * *

A few days pass, and after some extended meditation on the subject, Bruce Banner concludes that his attraction to Natasha Romanoff is inconvenient, but manageable. He's just a man who has been alone with his anger and shame for too long, and she's a beautiful, mysterious, ass-kicking superspy. It's human nature. He won't be the first man to have a crush on her, and he won't be the last.

He's been mildly attracted to one or two women since Betty; it always passes, and if it were just a physical attraction, he suspects that this time would be no different. The danger lies with the fact that while she is undeniably one of the most beautiful women he's ever met, she's also sassy, and witty, and challenges him intellectually. That's a potent combination. There's certainly potential for this small inconvenience to grow into a large problem, so he needs to nip this in the bud. Now.

Some slightly more focused meditation allows him to come up with a strategy. He just has to give himself a little distance, until this silly infatuation of his runs its course. That's easy enough, Tony has invariably got five or six projects going on at any one time, so there's plenty to do in the labs, along with his own work he's conducting when he has a spare moment. Tony has given him almost total access (second only to Pepper and JARVIS) to any and all Stark Industries tech he desires; most scientists would _kill_ to have the privilege. As a grad student he could only dream of having a lab like this, state-of-the-art equipment, nearly limitless resources to conduct any kind of experiment he likes, and an always-willing lab partner in Tony (especially if it involves fire or blowing something up.) So he's got plenty of distractions at his fingertips.

On top of that, if he needs a little extra motivation, he only has to picture what she'd do if she found out. Laugh at him perhaps, pity him, maybe it would even make her angry. He's not sure which would be worse. And quite frankly, he'd rather walk naked through Times Square than give Tony that kind of ammunition. If his best friend finds out, he, the rest of team, and probably the general population of New York City will never, _ever_ hear the end of it.

He still sees her around the Tower fairly regularly; Tony likes for them all to eat together whenever they can, and he's quite relieved about it. The others provide a natural buffer between himself and Natasha, allowing him to keep conversation to a minimum. Tony has a tendency to take over any conversation he is (or isn't) involved in, and usually manages to irritate everyone enough that they're all too busy shooting daggers at him with their eyes to notice that Bruce has quietly slipped away.

Well, Natasha and Clint probably do notice, he figures, but he doubts they particularly care. He's just part of the scenery of Avengers Tower to them; he's just kind of there.

Tonight, Tony corrals them all into the dining area with the promise of all the pizza they can eat and an open drink selection. Bruce suspects that this sudden outpouring of generosity has a lot to do with the fact that Pepper's in Tokyo on Stark Industries business and won't be back for a week. Pepper takes a lot of trips these days, and she's told Bruce in confidence that she's very glad he's come to live in the Tower with them, because she feels better having someone around to keep an eye on Tony, who can be dangerous if bored and left to his own devices.

Steve is the first to arrive. He helps himself to pizza but forgoes the large selection of alcohol in favour of a glass of water. In his head, Bruce counts to three. Steve is hard-pressed to do anything without earning some kind of sarcastic remark from Tony, and naturally, this time is no exception.

"Whoa, slow down there old man, you don't want to get onto the hard stuff too early, what kind of example is that for the children?"

Steve rolls his eyes. "If they want an example of what not to do in life, Stark, they have a shining example in you."

"Are you kidding? I got money, smarts, charm, good looks, the hottest chick in New York, and I'm a superhero," Tony reels off proudly. "Not to mention I got a buddy to do science with, the sweetest tech in the world and a rapier sharp wit. What else do I need?"

"Perhaps a personality transplant," Steve suggests, lightly. "Or maybe you could invent something to surgically reduce your enormous ego." He pretends to consider for a moment. "Or on second thought, don't, it'd probably malfunction and blow you up."

Bruce stifles a chuckle as Tony's eyes narrow. He will happily accept almost any slight on his personal character, but the moment someone insults his work, he takes offence. "All right, listen here you glorified action figure…"

Bruce tunes them out and reaches for a plate. When Steve and Tony get like this, it's usually best just to leave them alone to duke it out. They have an almost insatiable need to get under each other's skin, the unofficial leader of the Avengers and his unofficial second-in-command, and there have been times when Bruce has seriously considered stepping in to break them up, but so far, there's been no actual bloodshed.

He has long suspected that Steve sometimes provokes Tony on purpose, like now, and that he quite enjoys fighting with him. It's one of the rare times when he doesn't have to be good, righteous Captain America, but can just be Steve Rogers, who gets to have fun teasing his buddy. He's missed out on a lot of that, since he was on ice.

"Another lover's tiff, is it?" Clint's voice takes him by surprise, and his head whips round to see that both he and Natasha have arrived, holding a bottle of beer each and sinking into chairs. They move so silently that he rarely hears them coming, especially with Tony and Steve bickering next to him. "What set them off this time?"

"Nothing worth repeating."

Natasha is reaching towards the stack of plates, and Bruce hastily moves his hand away to avoid brushing against her arm, as though she could figure out what's going on with him just from that. Then again, she knows all about how to read and manipulate men, for all he knows, she could.

She notices his hasty retreat, he can tell because her eyes follow the motion for a fraction of a second, but she simply takes two plates, hands one to Clint, and proceeds to help herself to pizza.

The bandage is gone from her arm, he sees now, and she's moving it freely, so it's clearly healed. That's good. He also notices that both she and Clint are sweaty, and she's got her hair scraped back in a messy ponytail, the way she only bothers to do when they're sparring.

He hates himself for noticing all this. If he was as pedantic about his gamma radiation research as he is about cataloguing irrelevant details about Natasha Romanoff, perhaps the Other Guy would be just an imaginary monster for the comic books instead of his personal living nightmare.

But there's no point going down this road again. This was the kind of thinking that caused his suicide attempt, the day he realised that there was no easy way out of this particular mess. It's going to be him and the Hulk, together forever, until the end of days, outliving Tony, Clint, Natasha, even Steve. One by one, they'll fall, and he'll watch each one be buried, until they're all gone, some of the greatest friends he'll ever have. The one group of people he can sit in a room with and know that they see more than the Hulk in him.

There'll still be Thor, at least. But he's got his own problems, and a kingdom to help run, he won't have the time to comfort a lonely man with a monster within, and a thousand regrets.

No, in the end, it'll just be the two of them.

"Bruce?" This time it's Natasha's husky voice that breaks into his thoughts. Shamefacedly, he meets her eyes, can see something in them that almost looks like concern. "You might wanna grab yourself a couple slices before the Iron Garbage Disposal and Captain Crunch finish their little quarrel. They'll eat at least two pizzas between them, and you won't even get a look in."

"You OK, Banner?" enquires Clint, eyeing him curiously. "We lost you there for a while."

"Clint…" her voice is low as she cuts her gaze to her best friend, and Bruce almost misses the tiny shake of her head but can guess it's meaning. _Back off. Leave him be._

Bruce is grateful for her intervention, even though he knows that if he were any kind of man, let alone the hero they all insist he is; he'd be able to answer his teammate. He takes the box she's offering him, with a muttered word of thanks and a glum sort of smile, ignoring the way something seems to clench inside him when she smiles back.

The team go their separate ways after dinner and Bruce forgoes his usual evening session in the lab, choosing instead to sit on the balcony of his floor of the Tower, in the cool night air. The lights of the city that never sleeps begin to flare around him in the skyscrapers and on the street, each denoting another soft, breakable person that the Hulk could destroy if he ever got loose again. That's why he likes it up here, high above them, so they can go about their lives safe from him. It was the same in Calcutta; he only emerged to heal and do good, and could keep his distance for the rest of the time.

Then SHIELD came barging into his life again, with that red-haired Russian assassin leading the charge. Sometimes he wonders if Fury's decision to send her to recruit him was a strategic move, if he maybe thought Bruce would be distracted enough by the beautiful messenger, to not realise the message was the call to arms he'd never wanted to answer.

He wouldn't be totally wrong.

* * *

When he wakes up the next morning, it's to find the Tower in a flurry of activity. This can only mean one thing: a mission has come in. It's time for Earth's Mightiest Heroes to earn their keep.

'Dr Banner,' JARVIS's cool tones come flowing from the intercom, 'Captain Rogers requests a word with you before he leaves.'

"All right JARVIS, call me an elevator and I'll head right up there."

"Right away, Doctor Banner."

If he ever leaves the Tower, he's going to miss JARVIS. It's been disturbingly easy to get used to having Tony's AI at his beck and call.

He arrives on one of the topmost floors of Avengers Tower, which chiefly serves as the hangar for the quinjet when it isn't in use, as well as a storage space for Tony's suits that have malfunctioned or glitched in some way (it is far too dangerous to allow any of his technology to fall into the wrong hands, so he keeps them hidden away from prying eyes. Here, he finds Steve, decked out in his full Captain America regalia, shield in hand, waiting impatiently near the bank of elevators, who gives him a brisk nod of greeting.

"Doctor," he says, tersely. Bruce recognises the symptoms of him moving into battle mode, this uncharacteristically sharp tone, and fingers drumming on the edge of his shield are dead giveaways that he is anxious to be gone. "I called for everyone half an hour ago, and still no Stark."

If Bruce squints, he can see the faint outlines of someone (most likely, Clint) at the controls of the jet, preparing it to leave as soon as Steve gives the word. Natasha, he can't see, but assumes she's already on board.

Another elevator arrives, and Tony steps out of it, wearing his latest Iron Man suit, and sipping at a steaming mug. Steve casts him a look of clear irritation.

"Did you not hear me call for the Avengers to assemble?" he asks.

Tony rolls his eyes. "Keep your spangles on, Cap, I'm assembling. Why else would I be up at this ungodly hour?" His eyes light up at the sight of Bruce. "Don't tell me you've changed your mind, Banner," he says, excitedly. "We got room for one more."

Bruce and Steve both deny this idea, and Tony is clearly disappointed, showing his displeasure by handing the half-full cup to Bruce and walking away to prepare for departure.

"If this isn't a Hulk thing, then what is it?" he asks Steve now, genuinely curious.

"I still don't agree with your decision," says Steve. "But I respect it. However, we need some backup on this one so I've reached out to Thor. I told him to meet us there, but if he gets his wires crossed or something and winds up here first, give him our coordinates, and point him in the right direction, and keep an ear on the comms, like usual."

Since his refusal to fight, Steve often gives him jobs like this, that keep him involved with what they're doing without requiring him to fight. They are small, menial tasks that could easily be given to someone else but he doesn't mind. It allows him to help them, and keep innocent civilians safe. Win-win.

"I can do that."

"Hey Cap! Let's go already! Get your star-spangled ass over here." Natasha is standing by the quinjet ramp, gesturing for Steve to join them. Bruce wishes him luck, and watches as he sprints to the jet and up the ramp, which closes behind him. With a loud pulse of energy from Iron Man's thrusters, he takes off first and shoots out into the sky, the jet in hot pursuit. In a split second, they are gone, off to save the world again.

A few hours later, they've arrived at the HYDRA stronghold and everything appears to be going well. The comms are alive with chatter, Steve giving orders, Tony making jokes, and Clint relaying the positions of the enemy from whatever vantage point he's perched on today. He doesn't hear much from Natasha, but that's not unusual, she prefers to let her actions speak, or to put it simply, she's usually too busy beating up bad guys to chat.

But then he hears it.

"Well someone call Admiral Ackbar, cause it's a trap!" Bruce detects genuine fear under his best friend's usual bravado, and then Steve chimes in with an 'oh Christ.' That's about as close as Steve Rogers ever gets to swearing, so whatever it is has got to be bad.

He's saved from asking the question by Clint. "People, we've got problems. Four tanks and another hundred soldiers, heading this way, and we don't have either of our big-hitters. Where the hell is Thor?"

'Bruce?" He starts a little at the sound of his name. This is the first time he has ever been addressed directly during a mission he's listening in on. "You gotta track down Thor. As fast as you can. We need back-up."

"Guys." His blood runs cold as Natasha's low voice fills his earpiece. "I've got my back to a wall and twenty of them coming my way. Quit the chatter. I need to concentrate."

The comms go silent.

* * *

Luckily, Thor thuds down to earth about twenty minutes later, time that Bruce has spent frantically calling anybody he knows has even the slightest connection to the Asgardian to try and figure out where he is. It turns out that he misheard Steve (still unfamiliar with the concept of telephones) and flew to Australia instead of Austria. When he hears the news, he wants to leave immediately.

And take Bruce with him.

"Our friends need our assistance, Banner," he says, in his booming voice that ricochets off the walls. "We must go."

'But-'

"Enough of your protests!" Thor speaks over him. "Your concern for the safety of innocents does you credit Banner, but it is the height of dishonour to abandon one's friends when one has the power to help. I will not allow you to become such a man."

And before Bruce has time to protest, he grabs him, swings Mjolnir and they too, are off to save the world.

It's one of the most uncomfortable journeys of Bruce's life, and the Other Guy is bellowing in protest most of the way, to the point that he thinks he might transform once or twice. The curious thing though, is that under the Hulk's indignation at being picked up and carried around like a child, there is also a bit of satisfaction. After a while, he recognises it for what it is: bloodlust. The Hulk has become bored with their quiet lifestyle. He is eager to fight.

Thor drops him unceremoniously next to the quinjet, and summons up a thunderbolt that strikes the HYDRA base, leaving the air sizzling with power. Without a backward look, he takes flight once more and Bruce hears the almighty crash as he bursts through the roof, into the fray.

His earpiece was lost somewhere over the Atlantic, so he has no way of hailing the others to see how they're going, but he can hear a lot of screaming and repeated explosions from the base, so he supposes Thor's surprise appearance is doing its job. But he can't be sure.

His friends are in there. Natasha is in there. The Other Guy is fighting him for control, to be unleashed, desperate to get in there and SMASH! like Steve had told him to in New York.

It's building, and building. It's getting hard to hold him back. Bruce drops to the ground, uses every ounce of self-control he has to push the green monster back down inside him. He can't become the Hulk again.

Another explosion. More screams. The cracking, groaning sound of a beam collapsing. Out of the corner of his eye he can see one of the tanks. The gun barrel is moving, following a blur of red and gold, lining up the shot.

It's too much. The Other Guy is too strong. He succumbs.

When the roars of the Hulk fill the frozen air, Bruce Banner remembers no more.

* * *

Twenty men is not even close to the most that Natasha has had to take on at one time, but still, it's no picnic in the park either. She spins, flips, punches, kicks out, leaps, ducks, and uses her Widow's Bites when the opportunity arises. She's very glad she bullied Stark into fixing them up right away or she _may_ have been in a bit of trouble here.

She thinks of nothing but the enemies before her, takes them down one by one, like she's been doing all her life. No thought for the others, or for the greater mission they're here for, just the job at hand.

It takes a little longer than she'd like (the pizza from last night has taken its toll) but soon enough they're all exactly where she wants them: unconscious on the floor.

'Everyone still alive?" she enquires.

Predictably, Stark is the first to respond. "Yeah, just playing a little target practice with the tanks, and I'll give you one guess which one of us is the target."

"People are shooting at you, and they didn't invite me?" Clint breaks in. She sighs in relief. If her best friend is able to make stupid jokes, he's clearly okay. She scans the lower level of the base, where she and Clint have been working and can't see any movement.

"I think we're clear down here," she reports. "Everyone still alive went running upstairs when they heard the crash-what was that anyway? Was it Thor?"

"Yep that was our resident demigod's grand entrance," says Stark. "Thunder, lightning, chiselled abs, perfect hair, the whole enchilada."

"Jeez Stark, do I need to throw a bucket of cold water over you?" Natasha teases.

"You're hilarious Romanoff, If only we could all have a good laugh about it together, but you know, I'm a little busy right-well I'll be damned."

"What?" Both she and Clint demand to know at the same time.

"Told you, I'm busy. Come outside and see for yourself."

Natasha wrenches open a side door, and takes off toward the distinct sounds of a battle. She can hear explosions, gunfire, repeated blasts from Iron Man's repulsor beams, the crackling of flames, crunching metal…and an ear-splitting roar that she would recognise from miles away. Which is exactly where its owner is supposed to be, miles away.

"Is that-?"

"You can bet your black leather-suited ass on it, Widow," says Stark cheerfully. "He was a little late, but everyone knows that the party don't start till the Hulk walks in."

She rounds the side of the now-destroyed building (total destruction seems to be their trademark) to see the Hulk, bellowing in fury, tearing apart an armoured tank as though it were a toy, then throwing a second one across a clearing where it lands on its side. HYDRA agents begin spilling out and she draws her gun, hitting the first one square between the eyes. The Hulk deals with the other tanks as the rest of team gathers for the last part of the battle. She ducks as Steve's shield goes whizzing over her head, hits four enemies, and then returns to its master.

"Good to have him back, isn't it, Cap?"

"Sure is, Widow. Now let's finish this thing and go home."

"Aye, aye Captain," she mock-salutes.

"Shut up."

Ten minutes later, the job is done. They're all alive, and there's one less HYDRA base to worry about. Mission accomplished. There's just one more green, angry problem to take care of.

The Hulk, it seems, isn't ready for the battle to be over. It's been a while since he's been in control after all; so he doesn't seem to want to hand back over to Banner just yet.

Thor, Steve and Tony are standing in a semi-circle around the big guy, who is busily ripping up a tree by the roots, while she and Clint have retreated back to a safer distance. She's no coward, and she's not scared of him, but she knows he could snap her like a twig if he wants to, and it's pretty clear that the big guy isn't her biggest fan. Unlike his alter ego, she notes, but she'll think more on that later.

"So now what?" Clint pipes up. "We all just stand around and stare at him until he de-Hulks? Because I know a bunch of people looking at me like I'm a lunatic always brings _my_ anger levels right down."

'Shut up, Clint," she and Tony say, in unison, but Steve wearily shakes his head.

"He's right, we have to do something. Stark, didn't you say you were working on something?"

But Stark shakes his head too. "Veronica hasn't been tested yet. I have no idea if it'll work."

"Great."

At this point, the tree's roots part company with the ground, and the Hulk tosses it aside, snarling. As Clint predicted, he narrows his eyes when he sees them all watching him, and lets out a low growl. When he takes a step towards them, Thor springs into action, the only one of them with even close to enough physical strength to try and restrain him, but he is weakened from the battle, and the Hulk breaks his hold on him and slams him into the earth, and once more for good measure.

Steve raises his shield, and Tony primes his repulsors, and Natasha can see this is about to turn into yet another battle royale if nobody can stop it.

"Can someone call Pep and tell her to prepare a couple ice baths for us?" quips Tony. "I think we're gonna be sore tomorrow."

"This is exactly what Banner was worried about," Clint offers, unhelpfully. "If you'd all quit pushing him we wouldn't be in this mess."

Once again, Tony barks at him to shut up, but Natasha feels her best friend has a point. Bruce is going to feel guilty enough about the lives he's taken today, without hurting one of his friends as well. He carries a lot of guilt already; she knows because she carries it too. The last things he needs is to add more.

And then she has the idea. The Hulk may be standing in front of her but Bruce is in there too, and Bruce has a tendency to…react to her presence. Since he stitched up her wound, she's noticed that he tries to avoid physical contact at all costs. She puts it down to one of two reasons; that he hates her and never wants to touch her again, or that he liked it a little too much. And judging by the way she catches him looking at her sometimes, she's willing to bet it's the latter.

It's quite flattering really, if not a little unexpected, but that's by the by. The point is she might be able to use this, if the Hulk lets her get close enough to touch. It's a risk to be sure, but worth a try.

"Cover me," she tells the others and slips out from behind the tree.

* * *

 **OK, so I know the origin of the lullaby has been done before, and by writers more talented than myself so that is why I am offering you a choice for the next chapter. I can describe my version of how I think it went or skip over it and move on with the story. I see the lullaby as a very important development in their relationship so can't ignore it completely, but I'm happy to keep it in the background if people want.**

 **If you have a preference, or even just want to tell me what you think of the story in general, please do so.**

 **Part 3 should be up in a few weeks, but I have final exams and stuff that will need to come first.**

 **Thanks for reading!**


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